For implants in medullated bones of small Joints in particular, it is frequently necessary for the anchoring, especially for the primary anchoring, to keep ready a plurality of different sizes and shapes of shank in order to be able to respond in an optimum way to the individual characteristics of the individual patients and thereby above all during the first time after the implant, to guarantee a firm seat of the shank. This has previously demanded for every small Joint a large "assortment" of shanks differing little from one another; since in the case of small Joints the actual Joint part is usually connected inseparably to the shank, in the case of the known constructions of implant, even for every case a plurality of Joint prostheses have therefore to be made ready.